英語翻譯
Zonal power converters are used to produce the AC and lower voltage DC needed for the numerous ship loads.Load centers containing conventional AC and DC circuit breakers are still employed in such a system to feed (isolate and protect) the loads.In this type of power system,the current is actively (and instantaneously) limited by the power converters,dramatically reducing the available fault currents.When conventional circuit breakers are used in these systems,they have a relatively long clearing time due to the limited fault current.This causes the voltage on that critical bus to collapse for a significant time,negating some of the intended benefit of the DC distribution system.The current-limiting converters provide outstanding performance when feeding a dedicated load,but not when feeding a load center with multiple loads,and conventional circuit breakers further detract from thisperformance.
A solution to this system problem is the use of fast-acting solid state circuit breakers.Power semiconductors such as IGBTs and IGCTs are commercially available in voltage and current ratings that are compatible with the requirements for a ship distribution system.The microsecond response time of power semiconductors allows them to limit fault current to
low levels,and consequently limit the system energy that must be managed (i.e.dissipated).Such breakers can have“universal” configurations suitable for both DC and AC applications,and can be scalable for a wide range of ratings as typically required for a ship power distribution system.Their use can result in a superior power system that enables the full capabilities of a power converter-based ship distribution system.